This invention relates to a developer for full color copy. In more particular, this invention relates to a developer for full color copy in which original color images are duplicated in the combination of three color toners by means of a three color resolution exposure process or a three primary color subtractive process (which may include black toner).
Electrophotographic technique is widely applied, for example, to PPC, printer and the like. Recently, full color copied images have been able to be formed by piling different color toners (for example, Japanese Patent Laid-Open Sho 50-62442). As such a developer for full color copy is used mainly in order to duplicate pictures, photographs, graphics and the like, the copied images are generally solid. Therefore, the developer contains toner particles at a content of 6-12%, higher than a usual mixing ratio in a developer for only black. As a toner content increases, the contact possibility between toner and carrier becomes smaller and toner is supplied more often. Accordingly, because non-charged toner is often supplied, the delay of electrification-buildup of toner and the lack of toner charge amount are brought about, resulting in problems such as toner scattering, fogs and the like.
On the other hand, a resin component of toner contained in a developer for full color copy is the one having low viscosity from the view points such as transparency, adhesivity between plural color layers laminated on a copying paper and so there arises a problem of toner aggregations.
In addition, as a full color toner contains a different colorant depending on respective colors, each color toner has different charging properties. Accordingly, a carrier which can charge a color toner most suitably should be designed and researched depending on the properties of respective color toners. Even though color is same, a carrier should be also designed and researched when different kinds of colorants are contained.